es that there XUD on a very robust engine cylinder head
with a big preparation between 200 and 250 hp are the engine cylinder head can hold 100,000 km long? or is impossible?
Depends how you drive. If you drove once a year at full pelt it would last many years. If you drove it on a track everyday it would not last long at all.
My experiences with XUD head generally a 200hp block would last 5000-15,000 miles before it dropped a cup.
Tuning them results in temperature issues and cracked Precups in the head and some other less serious related issues.
Provided cooling is sorted, and precups are checked to be good BEFORE you will have a longer life with regular maintenance and suitable tune.
Good condition injectors and pump, are vital
Given the choice between Niall and the sheep. I would choose the sheep!
Whatever you do to them you just cannot pull the heat away from the pre-cups, there is just no win situation, unless you had bigger water pump, open up the galleys and thinner wall material to pull heat away quicker, they just heat up so quickly with serious boost/power.
Imagine 150kW and the only delivery of this energy is through the tiny pre-cup hole which is like 7mm or something, it soon heats up beyond what you can pull from it.